Table of Contents Author Guidelines Submit a Manuscript
International Journal of Photoenergy
Volume 2013 (2013), Article ID 507194, 8 pages
http://dx.doi.org/10.1155/2013/507194
Research Article

The Influence of the Ammonolysis Temperature on the Photocatalytic Activity of β-TaON

1Laboratory for Solid State Chemistry and Catalysis, Empa—Swiss Federal Laboratories for Materials Science and Technology, Ueberlandstrasse 129, CH-8600 Duebendorf, Switzerland
2Laboratory of Photonics and Interfaces, Ecole Polytechnique Fédérale de Lausanne (EPFL), Station 6, CH-1015 Lausanne, Switzerland

Received 28 November 2012; Accepted 31 January 2013

Academic Editor: Lukas Schmidt-Mende

Copyright © 2013 Songhak Yoon et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Phase-pure tantalum oxynitride (β-TaON) powders were synthesized by thermal ammonolysis of Ta2O5 powders. X-ray diffraction revealed an enlargement of the unit cell and an increase of the crystallite size with increasing ammonolysis temperature. Scanning electron microscopy showed reduced particle sizes for β-TaON synthesized at 800 and compared to the precursor oxide. With increasing nitridation temperature the Brunauer-Emmett-Teller surface area was reduced and the nitrogen content increased. UV-Vis spectroscopy showed a bandgap energy of 2.6–2.4 eV. The highest oxygen evolution rate of 220 μmol·g−1·h−1 was achieved for β-TaON synthesized at . The factors determining the photocatalytic activity of β-TaON powders were found to be the specific surface area and defects in the β-TaON.